Bomb fin shock absorber assembly

ABSTRACT

A bomb fin shock absorber assembly having a bomb fin support attached to a bomb by set screws, and a bellows type shock absorber slideably mounted on said support. A collar mounted on one end of the shock absorber is coupled to the bomb fin by link members such that the shock absorber will reduce the shock caused by the opening bomb fin, by collapsing at least in part.

Elite States patent 1191 Castor et a1.

[ Jan. 15, 11974 BOMB FIN SHOCK ABSORBER ASSEMBLY Inventors: Gary E. Castor, China Lake, Calif.;

William J. De Gain, Warren, Mich.

The United States of America as represented by the Scetretary of the Navy, Washington, DC.

Mar. 1, 1971 (Under Rule 47) Appl. No.: 119,769

Assignee:

Filed:

US. Cl ..l02/4,138/121,188/1C Int. Cl. F42b 25/02 Field of Search 188/1 C; 244/138 R,

References Cited UNITED STATES PATENTS 4/1970 Nishimura et a1 188/1 C 3,412,628 11/1968 De Gain 1. 188/1 C x 3,470,761 10/1969 Okahoto et a1. 188/1 6 x 2,857,510 10/1958 Haggerty et a1 a 188/1 c 3,228,634 1/1966 Chakoian et a1 102/4 x 3,461,531 8/1969 De Gain 29/1635 R 3,578,777 5/1971 De Gain 138/121 Primary Examiner-Samuel W. Engle Attorney-R. S. Sciascia, Roy Miller and R. W. Adams [57] ABSTRACT A bomb fin shock absorber assembly having a bomb fin support attached to a bomb by set screws, and a bellows type shock absorber slideably mounted on said support. A collar mounted on one end of the shock absorber is coupled to the bomb fin by link members such that the shock absorber will reduce the shock caused by the opening bomb fin, by collapsing at least in part.

1 Claim, 4 Drawing Figures PATENTEUJAH 15 m4 swan 1 BF 2 FIG. lb. ,7

[N '[i.\"[ A S. GARY E. CASTOR WILLIAM \J, [DE GAIN ROY MILLER ROBERT W. ADAIVIlJ ATTORNEYS.

PATENIEBJAH 15 m4 SHEET 2 0; '2

FIG. 2]

FIG. 3.

BOMB FIN SHOCK ABSORBER ASSEMBLY STATEMENT OF GOVERNMENT INTEREST The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION Prior bomb fin shock absorber assemblies are of the sleeve and plunger type. The shock absorber comprises two steel tubes and a collar. The collar isattached to one end ofthe first tube. The other end of the first tube is inserted into an expanded end of the second tube. When a force is applied longitudinally the first tube is forced farther into the second tube, deforming the second tube, and thereby dissipating the applied force.

The assembly additionally comprises a support, attached to the bomb by a retaining ring and garter spring, upon which the shock absorber is slideably mounted.

The sleeve and plunger type shock absorber assembly is unsatisfactory for use in high speed bomb delivery systems because it permits the shock load to become excessive before dissipation is initiated, its high initial shock resistance drops off sharply, and it is difficult to mass-produce due to required tolerances and stringent material and heat-treat requirements.

SUMMARY OF THE INVENTION The present invention is a bomb fin shock absorber assembly comprising a bellows type shock absorber in the form of a convoluted steel tube. A frist group of convolutions are reinforced by ribs extending longitudinally of said tube. A second group of convolutions are weakened by shaving their ridges. A collar similar to that of the prior assembly, but modified for the prescribed application, is mounted on one end of the shock absorber. The support, upon which the shock absorber is slideably mounted, is modified by substituting set screws for the retaining ring and garter spring of the prior assembly.

The present invention has the advantage over the prior device of early engagement with low initial and gradually increasing resistance, increased maximum release airspeed, reduced dispersion, improved reliability, simpler production, and reduced cost.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1a is a perspective view ofa bomb and bomb fin assembly, including the present invention, before fin opening;

FIG. lb is a perspective view ofa bomb and bomb fin assembly, including the present invention, after fin opening;

FIG. 2 is a perspective view of the shock absorber and collar of the present invention; and

FIG. 3 is a perspective view of a support used with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Bomb and bomb fin assembly 12 are shown in FIG. 1. FIG. Ia shows the bomb 10 and bomb fin assembly 12 immediately before fin opening is initiated. FIG. 1b shows the bomb fin assembly 12 fully opened,

exposing support 14, crushed shock absorber l6, collar 18, and link members 20.

Shock absorber 16 and collar 18 are shown in FIG. 2. Shock absorber I6 is a steel tube having a midsection 22 consisting of convolutions, and substantially cylindrical end sections 24 and 26 wherein end section 24 includes reinforcing ribs 38 for support. End section 24 is substantially cylindrical to provide clearance in the closed fin configuration for the blades of assembly 12; and end section 26 is substantially cylindrical for attachment to collar 18.

The midsection 22 is composed of subsections 28, 30, and 32. Subsection 28 has a plurality of convolutions with reinforcing ribs 34 disposed between the ridges of adjacent convolutions for support. The number of ribs 34 between adjacent ridges is directly related to the force necessary to collapse the convolution. Therefore, the degree of support desired determines the number of ribs chosen to be disposed between adjacent ridges.

Subsection 30 consists of unmodified convolutions. The wall thickness of midsection 22 remains unchanged except where shaved. That is, the wall thickness of subscctions28 and 30 through ridge, valley, and rib from convolution to convolution is a constant.

Subsection 32 includes a plurality of convolutions having shaved ridges 36. The wall thickness at ridges 36 is thereby reduced, providing convolutions that will collapse under light, or initial, load conditions.

As an example, shock absorber 16 can be made from steel having an AISI number 1008, and shaped by a hydraulic forming process. Collar 18 can be made from aluminum 6061T6.

Support 14 is shown in FIG. 3. Support 14 has a cylindrical member 40 upon which shock absorber l6 and collar 18 are slideably mounted, a threaded end 42 to which the fin assembly is fixedly mounted, and an enlarged end 44 designed to be mounted on the tail of bomb 10 by set screws 46. When assembled in operative form, cylindrical member 40, shock absorber l6 and collar 18 are coaxial.

The operation of the present invention is as follows: When the bomb 10 is released, the opening of the blades of bomb assembly 12 is initiated. The blades are thereafter forced by air pressure toward their full open configuration. The force applied to the blades is transmitted to collar 18 via link members 20. The force applied to collar 18 is absorbed by shock absorber 16, which is fixedly attached to collar 18, such as by a rolling process. The convolutions of subsection 32, which have weakened ridges 36 due to a shaving process, collapse under the initial light load of the fin 12 opening process. As the applied load increases, subsections 30 and 28 collapse in turn, dissipating the energy of the increasing load. When the blades of fin assembly 12 have been completely extended to fully open configuration, all of the convolutions of shock absorber 16 will have collapsed, resulting in a substantially shortened tubular structure (FIG. 1).

The shock caused by the opening bomb fin assembly 12, which causes considerable damage to the assembly of prior devices, is efficiently dissipated by the present invention. Additionally, the bomb release airspeed can be increased without reduction of reliability, thereby improving the pilot and aircraft safety factor.

What is claimed is:

3 ,785 ,290 3 4 l. A shock absorber for dissipating the force applied first end section is adjacent said second convoluted to a device attached to the absorber by collapsing in a section and said second end section is adjacent said predetermined manner, and, thereby, reducing the defirst convoluted section; and structive effect of the force on the device, consisting of: wherein the members interior surface at said second a tubular member having a solid wall with interior 5 convoluted section is identical to the interior surand exterior surfaces and first, second and third face at said third convoluted section; convoluted sections and first and second substana circumferentially uniform annular protuberance in tially cylindrical end sections wherein each said the wall of said member at the end of said first end convoluted section has a plurality of solid circumsection that is opposite the end adjacent said secferential roots and ridges longitudinally alternating 0nd convoluted section; in the wall of said tubular member; circumferentially spaced protuberances in the wall at a plurality of supporting ribs in each said root of said said first end section between and connecting said first convoluted section sonsisting of circumferen annular protuberance to said second convoluted tially spaced protuberances in the wall of each said section of a longitudinal length greater than the root joining adjacent ridges to provide increased longitudinal length of the protuberances of said longitudinal collapse resistance to said member at first convoluted section; and said first convoluted section; a collar attached to said member at said second end modified ridges in said second convoluted section section having a plurality of circumferentially consisting of a circumferentially uniform, flattened spaced flanges extending longitudinally of, and outexterior planar surface at each ridge parallel to the ward from, said second end section for mounting longitudinal axis of said member, and a circumfersaid device; entially uniform, reduced wall thickness in said such that predetermined and different amounts of member at each said flattened surface to provide a force are required to collapse, and are dissipated reduced longitudinal collapse resistance to said by collapsing, said first, second and third sections, member at said second convoluted section; and when said force is applied said second section wherein said third convoluted section is unmodified, collapses first, said third section second, and said and is between and connects said first convoluted first section last, until the force is absorbed. section to said second convoluted section, and said 

1. A shock absorber for dissipating the force applied to a device attached to the absorber by collapsing in a predetermined manner, and, thereby, reducing the destructive effect of the force on the device, consisting of: a tubular member having a solid wall with interior and exterior surfaces and first, second and third convoluted sections and first and second substantially cylindrical end sections wherein each said convoluted section has a plurality of solid circumferential roots and ridges longitudinally alternating in the wall of said tubular member; a plurality of supporting ribs in each said root of said first convoluted section sonsisting of circumferentially spaced protuberances in the wall of each said root joining adjacent ridges to provide increased longitudinal collapse resistance to said member at said first convoluted section; modified ridges in said second convoluted section consisting of a circumferentially uniform, flattened exterior planar surface at each ridge parallel to the longitudinal axis of said member, and a circumferentially uniform, reduced wall thickness in said member at each said flattened surface to provide a reduced longitudinal collapse resistance to said member at said second convoluted section; wherein said third convoluted section is unmodified, and is between and connects said first convoluted section to said second convoluted section, and said first end section is adjacent said second convoluted section and said second end section is adjacent said first convoluted section; and wherein the member''s interior surface at said second convoluted section is identical to the interior surface at said third convoluted section; a circumferentially uniform annular protuberance in the wall of said member at the end of said first end section that is opposite the end adjacent said second convoluted section; circumferentially spaced protuberances in the wall at said first end section between and connecting said annular protuberance to said second convoluted section of a longitudinal length greater than the longitudinal length of the protuberances of said first convoluted section; and a collar attached to said member at said second end section having a plurality of circumferentially spaced flanges extending longitudinally of, and outward from, said second end section for mounting said device; such that predetermined and different amounts of force are required to collapse, and are dissipated by collapsing, said first, second and third sections, and when said force is applied said second section collapses first, said third section second, and said first section last, until the force is absorbed. 